1. 22565 EMD : 1.2 : Fundamental of Design
1.2 Types of Loads
Load : It is defined as any external force acting upon a
machine part.
Dead or steady load
Live or variable load
Suddenly applied or shock load
Impact load
2. 22565 EMD : 1.2 : Fundamental of Design
Stress
Definition : Internal resistance offered by the body on the
various cross section due to some external system of forces
or loads act is called as stress.
Mathematically
Force
3. 22565 EMD : 1.2 : Fundamental of Design
Strain
Definition : When a system of forces or loads act on a body,
it undergoes some deformation. This deformation per unit
length is known as unit strain or simply a strain.
Mathematically
Force
4. 22565 EMD : 1.2 : Fundamental of Design
Types of stresses
Sr.
No.
Type of Stress Figure Formula
01 Tensile Stress
t = Force / Area
02 Compressive Stress
c = Force / Area
03 Shear Stress
= Force / Area
04 Bending Stress b = Bending Moment /
Section Modulus
05 Crushing Stress
or Bearing Pressure
Pb = Force / Equivalent
area under crushing
06 Torsional Shear
Stress
= Torque / Polar
Section Modulus
5. 22565 EMD : 1.2 : Fundamental of Design
Principal Stresses
Normal Principal Stress
Principal Shear Stress
6. 22565 EMD : 1.2 : Fundamental of Design
Stress – Strain Diagram for ductile material
Proportional Limit
Elastic Limit
Upper Yield Point
Ultimate Point
Braking Point
Braking Point
(Practical)
Lower Yield Point
Stress
Strain
7. 22565 EMD : 1.2 : Fundamental of Design
Stress – Strain Diagram for brittle material
Proportional Limit
Elastic Limit
Ultimate and Braking Point
Stress
Strain
8. 22565 EMD : 1.2 : Fundamental of Design
Numerical based on this will be continue in next
sessions…………..
